So we know that inflating a kite with Helium would not work but...
Aerogel could it be the answer for the whole kite market especially low wind (less struts) it is 99% air but solid up to 4000 times its weight. It can be home-made too...
Can it be pressurized? can it be inflated then deflated back into a specialized canister or something?
If anyone is good with chemistry could explore the feasibility?
www.aerogel.org/